1. Field of the Invention
The invention relates to a device for producing a drop of blood for blood sampling, and more particularly to such a device for moving and retracting a sharp lancet point to prick a patient's skin to produce a drop of blood.
2. Description of Related Art
Lancets are used to pierce the skin of a patient, usually through the finger. Blood then flows through the incision where it is collected for testing in a blood collection tube such as a capillary tube or pipette.
Historically, early lancets generally had a handle and a sharp lancet tip extending therefrom. However, numerous problems are inherent with such lancets such as controlling the depth and angle of penetration by the lancet tip, controlling the force of the insertion, and the psychological affect to the user of seeing the exposed lancet tip.
One attempt to avoid these and other problems with this early type of lancet was to create lancets having lancet tips that are spring loaded to be injected into and removed from the patient's skin. Typically, these devices hide the lancet tip both before and after the incision is made to prevent its view by the patient, to minimize trauma to the patient and to prevent inadvertent contact with the lancet. Examples of such a lancet injector are disclosed in U.S. Pat. No. 4,580,565 issued on Apr. 8, 1986 and its parent application U.S. Pat. No. 4,503,856, issued on Mar. 12, 1985, both of which are issued to W. D. Cornell and C. Evans and assigned to the assignee of the present invention.